Question

Among the hydrides of group 15, predict the hydride having lowest boiling point.

Answer 1

1. Ammonia (NH₃) has a high boiling point due to hydrogen bonding.
2. PH₃ has no hydrogen bonding and weak van der Waals forces, causing a low boiling point.
3. Boiling points increase from PH₃ to BiH₃ due to increasing van der Waals forces with molecular size.
4. Therefore, PH₃ has the lowest boiling point among group 15 hydrides.